1. Field of the Invention
This invention relates to means for driving a gun in which the barrels revolve during the loading operation, e.g. a Gatling gun.
2. Prior Art
In conventional Gatling guns, the power source, of whatever kind, has been coupled to the barrel cluster or rotor, to cause the rotor to rotate, which in turn, has driven the gun bolts, usually through a helical cam in the outer housing driving cam followers on the bolts. A torsion shaft drive of the rotor is shown in U.S. Pat. No. 2,989,900 issued June 27, 1961 to D. P. Grover. A recoiling barrel drive of the rotor is shown in U.S. Pat. No. 2,965,003 issued Dec. 20, 1960 and U.S. Pat. No. 3,071,043 issued Jan. 1, 1963, both to W. D. McThomas. Various gun-gas drives of the rotor are shown in U.S. Pat. No. 2,756,639 issued July 31, 1956 to J. R. Bird; U.S. Pat. No. 3,017,807 issued Jan. 23, 1962 to D. P. Grover; U.S. Pat. No. 3,041,939 issued July 3, 1962 to D. Dardick; U.S. Pat. No. 3,311,022 issued Mar. 28, 1967 to R. R. Bernard et al; U.S. Pat. No. 3,407,701 issued Oct. 29, 1968 to R. E. Chiabrandy; and U.S. Pat. No. 3,568,563 issued Mar. 9, 1971 to L. R. Folsom. In these conventional Gatling guns, the bolts are driven by a substantially helically shaped cam cut into the housing. Rotation of the rotor, in which the bolts are guided for reciprocation in longitudinal tracks, forces the bolt drive rollers against the cam to drive the bolts forward and back in ram and extraction strokes respectively. The slope of this cam limits the degree to which the housing diameter can be decreased. As the housing is made smaller in diameter, the cam steepens (i.e. approaches the perpendicular to the longitudinal axis until the driving angle becomes too steep and jams the bolt drive roller. In U.S. Pat. No. 3,834,272 issued Sept. 10, 1974 to R. A. Patenaude et al, an external power source separately drives the rotor and an actuator for the gun bolts.